The SNS (Social Networking System) is a system in which communication can be performed with each other based on a relationship with a friend of a user, a friend of a friend, or the like. Recently, information on a relationship between users on the SNS can be obtained via a Web API (Application Programming Interface).
For example, the following Patent Document 1 describes that a network image that shows a network structure representing a relationship between users in time series is displayed based on information representing an attribution of a user who is registered in the SNS or registration time and information representing a relationship between the users on the SNS or time when the relationship is established.